Technical Field
The present disclosure relates to a method of manufacturing a barrier film which includes depositing an oxide thin film on a substrate in a deposition manner as determined depending on the type of oxide and high-pressure thermal treating the thin film at a predetermined temperature and at a predetermined pressure. The thin film described herein can be manufactured at a low temperature, at a low cost and at a high yield. The moisture resistance of the barrier film can be improved, and transmittance can be 90% or more, as compared to a conventional method of manufacturing a barrier film by thermal treatment. The present invention also relates to a barrier film manufactured by the method.
Background Art
Electric cars are beginning to replace petroleum cars and the market has explosively grown and been led by various automobile companies.
For example, Tesla has about 249 published patents, yet a relatively small portion (about (35) are related to electric charging technology. Currently, charging of electric cars is performed by charging stations operated by global electric car companies and chargers for home use. There are advantages of combining electric cars with solar cell technologies.
However, solar cell charging systems have low efficiency and limited lifetime as compared to conventional systems. Accordingly, there is a need for prevention of deterioration in device efficiency and improvement of lifespan based on development of solar cell barrier films.
Inorganic films used as conventional barrier films in solar cells function as excellent barrier layers to osmosis, but have a problem of allowing permeation of moisture or oxygen due to physical defects such as pinholes and pore regions. Organic films have a problem of relatively high permeation when moisture or oxygen adsorbed on the surfaces of the films is permeated by diffusion. There was a lot of conventional research on improvement of moisture resistance by increasing substantial permeation movement routes using an organic/inorganic hybrid structure to solve these drawbacks of organic/inorganic substances. In addition, recently, use of graphene is receiving much attraction as a next-generation novel substance, as a barrier film has been attempted due to gas barrier properties and thin thickness, and technologies associated the use are thus developed.
In this regard, conventional barrier films using oxide thin films have been produced by vacuum deposition such as physical vapor deposition (PVD), chemical vapor deposition (CVD) and atomic layer deposition (ALD), and conventional research was focused on improvement of moisture resistance of barrier films by changing the type of materials, conditions and the like, rather than processes. In addition, oxide thin films formed by such a process had a limitation of needing additional high-temperature thermal treatment to improve properties thereof.
Furthermore, conventional hybrid barrier films are produced by PVD, CVD and the like as well as processes such as solution casting and blending. Such a production process has an economic problem of low mass-production efficiency due to a complicated multilayer stacking process. In addition, these processes are conducted at high temperatures for chemical bonding of thin films. These processes are inapplicable to flexible substrates having a low melting point. There are some flexible substrates having a high melting point. However, such substrates have a problem of a high production cost. In addition, barrier films using graphene are commercially unavailable because of technical difficulty in producing large-area graphene single layers.
Accordingly, the present invention provides a barrier film which is produced at low costs and high yield, exhibits excellent moisture resistance and high transmittance and is useful for packaging solar cells, and a method of producing the same. The barrier film can improve charge efficiency and lifespan of solar cells of electric cars. Such barrier films with improved moisture resistance can be used to establish electric car charging systems using solar cells.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.